Looper mechanisms for sewing machines



Jan. 16, 1962 H. HACKLANDER LOOPER MECHANISMS FOR SEWING MACHINES 5 Sheets-Sheet 1 Original Filed Sept. 14, 1956 42AM flTTORNEY Jan. 16, 1962 H. HACKLANDER 3,015,851

LOOPER MECHANISMS FOR SEWING MACHINES Original Filed Sept. 14, 1956 5 Sheets-Sheet 2 INVENT OR.

Hams; Haw/ naw F fig. 22., BY

A TTQf-PNEY Jan. 16, 1962 H. HACKLANDER LOOPER MECHANISMS FOR SEWING MACHINES Original Filed Sept. 14, 1956 5 Sheets-Sheet 3 IN VEN TOR. Hans Hack/under O 3 e 7/ ZI TTORNE Y Jan'- 16, 196 H. HACKLANDER LOOPER MECHANISMS FOR SEWING MACHINES 5 Sheets-Sheet 4 Original Filed Sept. 14, 1956 IN V EN TOR.

Hans Hack/under BY 22 fATTOR/VEY Jan. 16, 1962 H. HACKLANDER 3,016,351

LOOPER MECHANISMS FOR SEWING MACHINES Original Filed Sept. 14, 1956 5 Sheets-$heet 5 IN VEN TOR. Hans Hack/under W 67mm) ATTORNEY Unite The present invention relates to sewing machines and particularly to a loo-per mechanism for chain stitch sewing machines.

It is an object of this invention to provide an improved looper mechanism for a chain stitch sewing machine, the mechanics of which will adapt it for high speed operation.

It is a further object of this invention to provide a looper mechanism for a chain stitch sewing machine in which the only motions imparted to the looper bar are axial reciprocation and oscillation thereby facilitating making an oil-tight bearing and thus adapting it for use in an automatically lubricated sewing machine.

It is another object of this invention to provide a looper mechanism which can be readily converted from one in which the looper motion is transverse to the line of feed to one in which the looper motion is parallel to the line of feed.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those slc'lled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:

FIG. 1 is a vertical sectional view longitudinally of a sewing machine embodying the present invention.

PEG. 2 is a head end elevational view of the sewing machine illustrated in PEG. 1 with the face plate removed and parts broken away and in section.

PEG. 3 is a horizontal sectional view of the sewing machine of FIG. 1 with the cloth plate removed and its supporting bracket and the bed cover plate removed.

FIG. 4 is a fragmentary detail view in elevation of a modiication of the looper drive crank.

FIG. 5 is a fragmentary horizontal sectional view taken substantially on the line 55 of FIG. 4.

FIG. 6 is a fragmentary horizontal sectional view through the bed of a sewing machine embodying a modification of the looper mechanism in which the loopers operate in the line of feed rather than across the line of feed as in the sewing machine illustrated in FIG. 1.

FIG. 7 is a fragmentary sectional view taken substantially on the line 7-7 of FIG. 6.

FIG. 8 is a fragmentary sectional view taken substntially on the line 8-8 of FIG. 6.

The present invention is herein illustrated and described as embodied in the sewing machine forming the subject matter of my prior application Serial No. 609,836, filed September 14, 1956, now Patent No. 2,976,831, granted March 28, 1961, from which this application has been divided. While my prior application Serial No. 609,836 refers to the modification disclosed in FIGS. 6, 7 and 8, an illustration of this construction has been added to the present case to render the disclosure more definite and clear.

In the drawings there is illustrated a sewing machine having a frame including a bed 1 from the one end of which rises a standard 2 that carries a bracket arm 3 terminating in a head 4.

The bed 1 is divided by a transverse vertical Wall 5 upstanding from a bottom Wall 6, dividing the bed into a closed splash-lubricated compartment 7 and a space outside of the closed compartment 7 for accommodating the looper and feeding mechanisms of the machine. Within the bed 1, the closed compartment 7 is surrounded by the wall 5, and a front Wall 8, a rear wall 9 and an end wall 10. The bottom of the compartment 7 is closed by the bottom wall 6 having an access opening closed by a removable bottom plate 11, while a portion of the top of the compartment 7 communicates with the interior of the standard 2 and the remainder thereof is closed by a top cover plate 12.

A transverse bearing boss 13 is upstanding from the bottom wall 6 of the bed substantially at the longitudinal midpoint of the closed splash lubricated compartment 7. A main shaft 14 is journaled longitudinally of the bed of the machine in a bushing 15 in the boss 13 and in a bushing 16 carried by an insert 17 mounted in the end wall 10.

The stitching mechanism of the illustrated machine includes a needle bar 18 mounted for endwise reciprocation in the head 4 and carrying a pair of needles 19 at the lower end thereof. Endwise reciprocation is imparted to the needle bar 18 by means of a rock lever 20 connected by means of a link 21 to a collar 22 on the needle bar. The rock lever 28 is arranged longitudinally of the bracket arm 3 and is pivoted intermediate its ends on a pivot shaft 23. Rocking movement is imparted to the lever 20 by a pitman 24 connected at one end to the rock lever 2i) and at the other end to a crank 25 on the main shaft 14.

Cooperating with the needles 19 is a loo-per mechanism comprising a looper bar 26 mounted for oscillation and for axial sliding movement in a direction parallel to the axis of the main shaft 14 in a bushing 27 mounted in a boss 28 extending upwardly from the bottom wall 6 and a bushing 29 mounted in the wall 5. A looper carrier 31 is mounted on the looper bar 26 by means of a split ring connection having a clamping screw 31. A pair of straight-line type, threaded, chain stitch loopers 32 are mounted on the looper carrier 39, the loopers having cylindrical shanks that are received within vertical bores in the looper carrier 39 and locked in adjusted position by set screws 33. Each of the loopers 32 is adapted to cooperate individually with one of the needles 19 in the formation of a line of two-thread chain stitch stitches, axial reciprocation of the looper bar 26 imparting loop-seizing or advance and loop-shedding or return movements to the loopers 32, and oscillation of the looper bar 26 imparting the loop-spreading or needle-avoiding motions to the loopers.

The looper bar 26 extends through the bushing 29 into the closed compartment 7 and the end thereof is secured by a universal joint 34 to one end of a connecting rod 35. The universal joint 34 comprises a yoke 36 on the end of the looper bar 26, the yoke being apertured to receive pivotally a pin 37. Mounted on the pin 37 between the arms of the yoke 36 and secured thereto by a set screw 38 is a sleeve 39 having integral therewith a yoke 40 apertured transversely to the axis of the sleeve 39 to receive pivotally a pin 41. Mounted on the pin 41 between the arms of the yoke 40 and secured thereto by a set screw 42 is a sleeve 43 formed upon the end of the connecting rod 35.

The opposite end of the connecting rod is secured by a universal joint 44 to a crank pin 45, the universal joint 44 comprising a sleeve 46 formed upon the end of the rod 35 and mounted upon and secured by a set screw 47 to a pin 48 that is pivotally mounted in the arms of a yoke 49 having integral therewith a hub or sleeve 50 that is in turn pivotally mounted upon the crank pin 45. The sleeve 50 is held on the crank pin 45 by a screw 51.

The drive for the looper mechanism comprises a bevel gear 52 secured upon the end of the main shaft 14 which extends through the bearing bushing 15. The gear 52 meshes with a similar gear 53 on a looper drive shaft 54 journaled for rotation transversely of the bed in a bearing bushing 55 in the rear wall 9 and in a bearing bushing 56 in a boss 57 rising from the bottom wall 6 of the bed at a point spaced inwardly from the front wall 8. Mounted upon the end of the shaft 54 is a counterbalanced crank plate 58. Endwise sliding motion of the shaft 54 is prevented by the crank plate 58 and a collar 59 which are arranged upon opposite sides of the bearing bushing 56.

The crank pin 45 is integral with a mounting plate 60 and is formed with the axis thereof skewed rather than normal to the plane of the front surface of the plate 60. The plate 60 is mounted in a groove 61 in the face of the crank plate 58, which grooves provide for adjustment of the plate 60 in a direction radially of the axis of the looper drive shaft 54, and it is secured in adjusted position by screws 62 that extend through elongated slots 63 in the plate 60 and are screwed into the crank plate 58.

In FIGS. 4 and there is illustrated a means for adjusting the axis of the crank pin 45 toward and away from a position parallel to the axis of the shaft 54, which means comprises an adjusting screw 64 threaded through one end of the mounting plate 60 remote from the crank pin 45 and abutting against the crank plate 58 so that when the screws 62 are tightened, the mounting plate 60 will abut against the crank plate 58 only at the screw 64 and at the forward edge, thereby tilting the mounting plate 60 relatively to the crank plate 58.

In operation, upon rotation of the main shaft 14, rotation will be imparted to the looper drive shaft 54 which carries the crank pin 45 and will therefore rotate the crank pin 45 about the axis of the shaft 54. The throw of the crank pin 45 will, through the connecting rod 35 and the universal joints 34 and 44, impart axial sliding to the looper bar 26, which will effect loop-seizing and loop-shedding movements of the loopers 32. At the same time, because of the skewed axis of the crank pin 45, it will gyrate as it rotates about the axis of the shaft 54, which gyration will be transmitted to the looper bar 26 for imparting oscillation thereto that will effect the loop-spreading or needle-avoiding motions of the loopers 32. Adjustment of the loop seizing and loop-shedding motions of the loopers is provided by the screws 62 and the slots 63 and adjustment of the loop-spreading motions of the loopers may be provided by the adjusting screw 64.

As seen in FIG. 1, the looper drive shaft 54 is disposed above the level of the looper bar 26. The mechanics of this construction will produce the desired rapid loop-seizing motion of the looper bar and a retarded loop-shedding motion.

For assembly purposes, there is provided an aperture 65 in the rear wall 9 and an aperture 66 in the front wall 8 in axial alignment with the looper drive shaft 54, which apertures are closed by cover plates 67 and 68, respectively. The aperture 66 is large enough to permit passage therethrough of the looper drive shaft 54 with crank plate 58 and the mounting plate 60 assembled thereon.

In the above construction in which the looper motion is longitudinally of the bed, the number of needles and cooperating loopers is limited to two or three and they are limited to relatively narrow gauges. One of the basic objectives of the present invention is to provide a universal sewing machine which can be readily modified and fitted for different specific sewing operations. In accordance with this objective, one of the primary ad vantages of the present looper mechanism is that there can be readily substituted therefor a looper mechanism in which the loopers move transversely of the bed as in the above mechanism, or in other words, in which the loop seizing motion of the loopers is in the line of feed rather than across the line of feed. Thus, there can be accommodated a larger number of needles and/ or wider gauges. In FIGS. 6, 7 and 8, there is illustrated a looper mechanism in which the loop-seizing motion is in the line of feed. To appreciate the simplicity of the substitution of this looper mechanism for that disclosed in FIGS. 1-3, it is necessary to revert to FIGS. 1-3 for an understanding of the associated features of the machine.

Included in the means for lubricating the feeding and looper mechanisms in the bed of the machine, which are outside the closed lubrication compartment 7, is an oiler 69 in the form of a cylindrical plug extending through a bore 70 in the wall 5 in axial alignment with the main shaft 14. The oiler 69 extends into the closed compartment 7 and has an oil collecting cavity 71 within the compartment 7. The oiler 69 has a wick-filled axial bore that communicates with each of a plurality of wick-filled tubes, such as the tube 72, which conducts lubricant to the feed advance mechanism and the tube 73 that conducts lubricant to the feed lift eccentric. The wall 5 is also provided with a bore 74 that is provided for accommodating a pivot shaft of a differential feeding mechanism that may be fitted on the machine (see US. patent application Serial No. 693,927, now Patent No. 2,974,617, granted March 14, 1961, which is also a division of application Serial No. 609,836). When the machine is not provided with a differential feeding mechanism, the bore 74 is closed by a plug 75.

Since a differential feeding mechanism is not used in a machine having a large number or wide gauges of needles, the bore 74 is available to be used in a machine having loopers in which the loop-seizing motion is in the line of feed. Thus, as seen in FIG. 6, the oiler 69 is mounted in the bore 74 rather than in the bore 70, leaving the bore 70 available for journaling the extension of the main shaft 14 as hereinafter explained.

With reference to FIGS. 6, 7 and 8, when the machine is fitted with loopers in which the loop-seizing motion is in the line of feed, thus adapting the machine for a large number of needles and for wider gauges, the main shaft 14 is replaced by a main shaft 14a that extends through the compartment 9 and is journaled at the end in a bushing 76 mounted in the bore 70 in the wall 5. For assembly purposes, the main shaft 14a is made in two parts connected together by a coupling 77. The looper drive shaft 54 is replaced by a looper drive shaft 54a that is arranged normal to the main shaft 144; and is journaled in a bushing 78 in the boss 57 and in a bushing 79 mounted in a bearing plate 80 that replaces the cover plate 68. Rotation is imparted to the looper drive shaft 54a upon rotation of the main shaft by the meshing bevel gears 52 and 53. The looper bar 26 is replaced by a looper bar 26a that is journaled for oscillation and for endwise reciprocation in the bearing bushings 27 and 29 and ex tends into the compartment 9. A looper carrier 39a is mounted upon the looper bar 26a by means of a split ring connection having a clamping screw 31a. The

looper carrier 30a carries a pair of loope'rs 32a which are secured thereto in adjusted position by set screws 33a.

The loopers 32a are mounted transversely of the bed or parallel to the line of feed for loop-seizing motion in a direction opposite to the normal direction of feed. Advance and return or loop-seizing and loop-shedding motions are imparted to the loopers 32a by oscillation of the looper bar 2611. Oscillation is imparted to the looper bar 26a upon rotation of the main shaft 14a by a counterbalanced crank 81 formed on the main shaft 14a having a ball-bushing 22 that is embraced by the strap end of a pitman 83. At its other end, the pitman 83 has a universal connection through a ball-and-socket joint 34 with the free end of a crank arm 85 secured to the looper bar 26a. The universal connections provided by the ball bushing 82 and the ball-and-socket joint 84 permits end- Wise movement of the looper bar 26a relatively tothe main shaft 14a, which comprises the loop-spreading or needle-avoiding movements of the loopers.

Endwise movement is imparted to the looper bar 26a by an adjustable eccentric 86 mounted upon the looper drive shaft 54a. The eccentric comprises a crank plate 87 mounted on the shaft 54a, as by screws 88, and having a diametrically arranged undercut slot 89. The crank plate 87 carries a slide member 90 comprising a plate 91 slidably mounted in the slot 89 and having an integral eccentric element 92, the slide member 90 being provided with an elongated slot 93 that receives the shaft 54a and accommodates movement thereof relatively to the shaft 54a for adjusting the eccentricity of the eccentric element 92. An adjusting screw 94 cooperates With the slide member 90 in the usual fashion to efiect adjustment thereof diametrically of the shaft 54a. The eccentric element 92 is embraced by the strap end of a pitman 95 that is connected through a universal joint 96 to the looper bar 26a. The universal joint 96 comprises a sleeve 97 formed on the end of the pitman 95 and having a pin 98 secured in the bore thereof by a set screw 99. The ends of the pin 99 are mounted in the arms of a yoke 100 having a sleeve 101 that is mounted on the end of the looper bar 26a.

From the above it will be seen that a single basic machine can be built up to provide either a looper mechanism in which the loop-seizing motion is in the line of feed or one in which it is transverse to the line of feed, or once assembled it can be readily converted. To obtain this convertibility the bed is adapted to be provided with three axially aligned main shaft journaling means, i.e., the bushing 16 carried by the end wall 10, the bushing 15 in the lug 13, and the bushing 76 in the transverse wall 5, and the bed is also adapted to be provided with three axially aligned looper shaft journaling means, i.e., the bushing 55 in the rear Wall 9, the bushing 79 in the front wall, and the bushings 56 or 78 in the lug 57. The lug 57 is located longitudinally of the machine between the lug 13 and the transverse wall and transversely of the machine between the aligned axis of the main shaft journaling means and the front wall 8. Thus, the journaling means can be used selectively to accommodate the different arrangements, the main shaft bushings 15 and 16 and the looper drive shaft bushings 55 and 56 being used for the arrangement having the loop-seizing motion transverse to the line of feed, and the main shaft bushings 15, 16 and 76 and the looper drive shaft bushings 78 and 79 being used for the arrangement having the loop-seizing motion in the line of feed.

The convertibility of the present looper mechanism has been obtained without sacrificing or compromising as to the operation of the machine and particularly the operation of the machine when fitted for loop-seizing motion transverse to the line of feed, which is the more common arrangement since it is better adapted for extremely high speed operation and produces better stitching and which is the more critical since it must perform at higher operating speeds. In the construction in accordance with this invention, the looper mechanism having the loop-seizing motion transverse to the line of feed is a. relatively light and free running mechanism that is adapted for high quality sewing at very high operating speeds, is dependable, durable and efiicient, it is adapted to be well balanced for vibration free operation, is relatively inexpensive, can be readily assembled and adjusted, and, having an axially .moving looper bar, can be readily sealed at the point where it emerges from the closed splash lubricated compartment, thus adapting it for use in an automatically lubricated sewing machine.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a chain stitch sewing machine having a bed including a closed splash lubricated compartment, a rotary main shaft journaled longitudinally in said bed and extending into said closed compartment, a looper bar arranged parallel to said main shaft and mounted in said bed for oscillation and for axial reciprocation and having one end extending into said closed compartment, a looper mounted on said looper bar outside of said closed compartment and arranged for loop-seizing motion upon axial movement of said looper bar and for needle-avoiding motion upon oscillation of said looper bar, and means for actuating said looper bar comprising a looper driving shaft journaled transversely in said bed within said closed compartment and arranged perpendicular to and spaced vertically from said looper bar, operative connections between said main shaft and said looper driving shaft for imparting rotation to said looper driving shaft upon rotation of said main shaft, a crank element carried by said looper driving shaft and arranged upon an axis skewed with respect to the axis of said looper driving shaft, a link, means including a universal joint for connecting a second universal joint for connecting one end of said link to said looper bar and means including the other end of said link to said crank element, whereby, upon rotation of said looper driving shaft, the throw of said crank element will effect axial reciprocation of said looper bar and the gyratory action imparted to said crank element upon rotation thereof about the axis of said looper driving shaft will effect oscillation of said looper bar.

2. In a chain stitch sewing machine having a bed including a closed splash lubricated compartment, a rotary main shaft journaled longitudinally in said bed and extending into said closed compartment, a looper bar arranged parallel to said main shaft and mounted in said bed for oscillation and for axial reciprocation and having one end extending into said closed compartment, a looper mounted on said looper bar outside of said closed compartment and arranged for loop-seizing motion upon axial movement of said looper bar and for needle-avoiding motion upon oscillation of said looper bar, and means for actuating said looper bar comprising a looper driving shaft journaled transversely in said bed within said closed compartment and arranged perpendicular to and spaced vertically from said looper bar, operative connections between said main shaft and said looper driving shaft for imparting rotation to said looper driving shaft upon rotation of said main shaft, a crank element carried by said looper driving shaft and arranged '3 upon an axis skewed with respect to the axis of said looper driving shaft, a link, means including a universal joint for connecting one end of said link to said looper bar and means including a second universal joint for connecting the other end of said link to said crank element, said closed compartment having an aperture aligned axially with said looper driving shaft and larger than the looper driving shaft and the crank mechanism mounted thereon whereby said crank mechanism may be preassembled on said looper driving shaft and then inserted References Cited in the file of this patent UNITED STATES PATENTS Corey et al. Aug. 23, Nash Feb. 28, Krasa Sept. 5, Christensen et al. Apr. 17, Quist Apr. 28,

FOREIGN PATENTS Germany Mar. 12, Germany Nov. 28, 

